Electrical properties of (Y0.08Sr0.92)1-xTi0.6Fe0.4O3-δ mixed conductor

Various compositions in the system of A-site deficient perovskite (Y0.08Sr0.92)1-xTi0.6Fe0.4O3-δ (x = 0.05, 0.07, 0.10) was synthesized at 1350 °C in air by sol-gel method. The effects of A-site deficiency in (Y0.08Sr0.92)1-xTi0.6Fe0.4O3-δ on the phase structure, electrical conductivity and ionic conductivity have been investigated. Crystal structure remains cubic perovskite among the all compositions, which means Y, Fe co-doping and A-site deficiency do not negatively affect the formation of cubic perovskite structure. Partial oxygen ionic conductivity decreases with A-site deficiency amount increasing, which may be attributed to the tendency for oxygen vacancy ordering. The n-type electronic conduction in air increases with A-site deficiency amount increase. The behavior should be attributed to the decrease of [Fe′Ti][Fe′Ti] and [h][h] due to the possible ionization reaction of ferric iron. The total electrical conductivity of (Y0.08Sr0.92)1-xTi0.6Fe0.4O3-δ (x = 0.05, 0.07, 0.10) varies from 0.11 S·cm−1 to 0.26 S·cm−1 at 800 °C and the ionic conductivity varies from 0.012 S·cm−1 to 0.022 S·cm−1 at 900 °C.